This invention relates generally to combustors and more particularly to a low pollution combustor for gas turbine engines.
During the process of combustion, maximum efficiencies are achieved when all the carbon and hydrogen have been converted to carbon dioxide and water, respectively. However, at high temperatures the two latter compounds break down, at least partially, into other substances such as carbon monoxide and hydrogen. At still higher temperatures, some of the nitrogen of the air reacts with any oxygen surplus to the combustion requirements, to form nitric oxide. Depending upon the exhaust conditions, many other products may appear in trace quantities.
In present day gas turbine combustors, fuel is injected into the combustion chamber where it vaporizes, mixes, and burns and is then diluted to reduce the temperature before entering the turbine. Pollutants such as carbon and carbon monoxide are generated therein by poor mixing, poor combustion, and the result of the addition of cooling air which quenches the chemical reaction. Nitric oxide is generated by high temperature and long residence time of the gases in the combustion chamber.
Accordingly, it is an object of this invention to provide a low pollution combustor which more effectively provides combustion of the air-fuel mixture and thereby reduces the pollutant found in the exhaust.
A still further object of this invention is to provide a low pollution combustor having an axially movable baffle for controlling air flow to the primary combustion zone.